Drug delivery through the skin has a variety of applications and forms such as analgesic patches, nicotine patches, or birth control patches, because of its convenience in use. Drug delivery through the skin mainly involves the delivery through the skin into systemic circulation, but drugs such as therapeutic agents for atopic dermatitis, cosmetics for whitening or wrinkle improvement, etc. are used for the transport of drugs into the skin organ itself. Despite the convenience and functionality, there are many difficulties in drug delivery through the skin, due to the skin structure. Thus, it is difficult to develop drugs permeating the skin. The outermost layer of skin has a cornified layer which is composed of about 10 to 15 layers of corneocytes having a thickness of about 10 μm to 45 μm, and this cornified layer has the form called the “brick and mortar” structure. In the cornified layer, the brick structure is composed of corneocytes containing abundant keratin, and the mortar structure is composed of lipids such as ceramide, fatty acid, or wax which fill the space between corneocytes. This structure prevents loss of internal moisture from skin surface and external attacks. However, this structure has the property of very low permeability as faithfully corresponding to its functions. Only molecules having low molecular weight of 500 Da or less can pass through the skin by diffusion, mainly, through the intracellular lipid layer of the mortar structure, or the hydrophilic structure between lipid layers. Such drug delivery through the skin can be greatly influenced by the properties of the drug. Drug delivery through the skin may also occur through the structures such as sweat glands, skin pores, sebaceous glands, in addition to the direct passage through the skin surface.
Under this background, many studies have been actively conducted, to develop drugs which cap pass through the skin to be uniformly distributed throughout the skin regardless of size or property of the molecule, and drug delivery methods. For example, Korean Patent No. 1054519 discloses a human growth hormone-derived peptide which is more excellent in stability and skin permeability than the natural human growth hormones, and a composition including the same. Korean Patent No. 1104223 discloses an IL-10 derived peptide which has the same functions as human IL-10 (interleukin-10) and is more excellent in stability and skin permeability than the natural IL-10, and a composition including the same. However, since these peptides themselves exhibit functionality, there is a disadvantage that they cannot be used as a carrier for drug delivery. Therefore, a skin permeable peptide which can be used in the treatment of skin diseases and enhancement of skin permeability of pharmaceutically active compositions has been developed (U.S. Pat. No. 7,659,252). This peptide is advantageous in that it exhibits excellent skin permeability and can be also used as a carrier for transdermal delivery of other drugs. However, this peptide, once it passes through the skin, is consumed through the circulation system in the body, and thus drugs for targeting the skin cannot exhibit their specific effects.
Under this background, the present inventors have made strenuous efforts to develop a skin permeable peptide which can be used as a carrier for transdermal delivery of drugs and also has the property of remaining in the skin, and as a result, they have developed an isolated peptide having any one amino acid sequence of SEQ ID NOs. 1 to 10, thereby completing the present invention.